DNA computer detects, treats test tube disease. 

ABC News Online 
April 29, 2004
http://www.abc.net.au/news/newsitems/s1097298.htm

Scientists have come a step closer to creating a minuscule 
DNA computer that may one day be able to spot diseases like 
cancer from inside the body and release a drug to treat it. 

Professor Ehud Shapiro and researchers at Israel's Weizmann 
Institute constructed the world's smallest biomolecular 
computer a few years ago. 

Now they have programmed it to analyse biological information 
to detect and treat prostate cancer and a form of lung cancer 
in laboratory experiments. 

"We've taken our earlier molecular computer and augmented 
it with an input and output module. Together the computer 
can diagnose a disease and in response produce a drug for 
the disease in a test tube," Professor Shapiro told Reuters.

The microscopic computer is so minuscule a trillion could 
fit in a drop of water. 

Its input, output and software are made up of DNA molecules 
which store and process encoded information about living 
organisms. 

"Our work represents the first actual proof of concept and 
the first actual demonstration of a possible real-life 
application for this kind of computer," Professor Shapiro 
added. 

The findings, which are published online by the science 
journal Nature and were presented at a symposium in Brussels, 
could transform how diseases like cancer are treated in the 
future. 

Instead of biopsies to remove cancerous tissue, which then 
must be analysed in the laboratory, the DNA computer could 
potentially diagnose the disease within the tissue in the body. 

"Our medical computer might one day be administered as a drug, 
and be distributed throughout the body by the bloodstream to 
detect disease markers autonomously and independently in 
every cell," Professor Shapiro said. 

It could enable doctors to treat cancer in its earliest stages 
before tumours have formed and to deliver drugs to hard to 
reach cells if the disease has spread to other parts of the 
body. 

Different inputs could be used to detect other diseases. 

"It could work for any illness for which there is a particular 
pattern of over-expression or under-expression of genes which 
is characteristic for the disease," according to Professor 
Shapiro. 

He readily admits that a DNA computer roaming around the body 
spotting and treating disease is still a long way away. 

"There are many, many hurdles. It could take decades," 
Professor Shapiro said, adding that he and his colleagues 
had not expected to accomplish this step so quickly. 

Professor Shapiro's DNA computer is a molecular model of 
one of the simplest computing machines, the automaton, which 
can answer certain yes or no questions. 

It uses enzymes, which manipulate DNA, as the computer's 
hardware. The computer is pre-programmed with medical 
information and detects markers, or concentrations of 
certain molecules of RNA (a cousin of DNA) which are 
overproduced or underproduced to detect the cancer. 

If the markers signify a disease, the output releases a 
molecule similar to an anti-cancer drug to destroy the 
cancerous cells. 

Leonard Adleman, of the University of Southern California, 
pioneered the field of DNA computers a decade ago by using 
DNA in a test tube to solve a mathematical problem. 

--Reuters